Is having a high top number (systolic) blood pressure, but a normal bottom number (diastolic) cause for concern?

Yes. If you have a diastolic number — the bottom number of a blood pressure measurement — less than 90 millimeters of mercury (mm Hg) and a systolic number — the top number of a blood pressure measurement — greater than 140 mm Hg, you have a common type of high blood pressure called isolated systolic hypertension.

Isolated systolic hypertension can be caused by underlying conditions such as artery stiffness, an overactive thyroid (hyperthyroidism) or diabetes. Occasionally, it can be caused by heart valve problems.

It is the most common form of high blood pressure in people older than age 60, but it is possible for younger people to be affected by this type of high blood pressure as well.

Doctors now know that high systolic pressure is as important as high diastolic pressure — and even more important in people older than age 50. Having a high systolic pressure for a long period of time can increase your risk of having significant cardiovascular problems, such as heart attack or stroke.

The recommended goal for systolic pressure for younger people has been less than 140 mm Hg for many years. For people who are 60 or older, the recommended treatment goal remains at less than 150 mm Hg. However, new research has found that there may not be a one-size-fits-all answer to what your blood pressure goal should be. Even a 10- to 13-point decrease in your systolic measurement could help reduce your likelihood of experiencing major cardiovascular problems.

Isolated systolic hypertension can lead to serious health problems, such as:

Stroke

Heart disease

Chronic kidney disease

Your high blood pressure will need to be controlled with medications in order to prevent health problems. However, if your treatment lowers your diastolic pressure too much, you could be more likely to have a heart attack or stroke. So if you have isolated systolic hypertension, your doctor may recommend that your diastolic pressure not be reduced to less than 70 mm Hg in trying to reach your target systolic pressure.

Your doctor might also recommend certain lifestyle changes that could help improve your systolic pressure reading, in addition to your treatment with medication. Decreasing the amount of salt in your diet, losing weight if you're overweight or obese, increasing your physical activity, avoiding smoking, and limiting how much alcohol you drink can all help manage your blood pressure. Your doctor will need to monitor your treatment and lifestyle changes closely to ensure you receive the maximum benefit.

James PA, et al. 2014 evidence-based blood pressure guideline for the management of high blood pressure in adults: Report from the panel members appointed to the Eighth Joint National Committee (JNC 8). JAMA. 2014;311:507.

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